Is it OK to stay unmarried?

The simple answer is no. Different studies will say that married people are happier—but its not necessarily that marriage makes them happy. The happier you state you are, the more likely you are to get married in the first place. Its unfair to compare the married population with the unmarried population.

Can a girl stay unmarried?

Getting married is still the norm, and for women to either delay marriage or choose to remain single is the exception. In India, a womans status is still linked to marriage, who she marries, whether she has produced a male child, and whether she is an obedient and dutiful wife and daughter-in-law.